This tasteful bit of signage accessorizes the Student Administration Office at Queen Mary College in London:
Important Message to Invigilators [exam proctors to you and me]
Candidates attempting to cheat in an exam by writing on a part of their body must be reported to the chief invigilator immediately.Please speak to an exam attendant who will contact the student administration office. Keep the students under close observation to ensure that they do not attempt to erase the evidence.